DeChellis received the 2009 Big Ten Coach of the Year award and 2006 National Coaches vs. Cancer Man of the Year. He was born in the Pittsburgh, Pennsylvania suburb of Monaca and has three daughters with his wife Kim.
DeChellis was the head coach of the East Tennessee State University Men’s Basketball program from 1996 to 2003, winning three Southern Conference north division titles (2000–03). Prior to joining East Tennessee State, DeChellis served as an assistant coach at Salem College (WV) and Penn State University.
In 2003, DeChellis inherited a Penn State team that had gone 7–21 the previous two seasons. In his first two seasons, Penn State won 9 and 7 games, respectively, before finishing 15–15 in 2005–06. During this time, DeChellis recruited Geary Claxton and Jamelle Cornley to PSU.
In 2007–08, Penn State entertained hopes of being a dark-horse contender in the Big Ten and possibly even winning enough games to get into the NCAA Tournament. Those hopes were quickly disintegrated when senior forward Geary Claxton went down with an anterior cruciate ligament injury in January. The Lions were plagued with more injuries, when junior forward Jamelle Cornley battled a bruised knee all season. The Lions went 15–16 in the 2007–08 season in a team that started four freshman in the end. Highlights included upset wins over top-10 ranked Michigan State and top-20 ranked Indiana.
DeChellis led the Lions to a 21–10 regular season in 2008–09, equaling the Penn State record for regular-season wins. The Nittany Lions were 10-8 in the Big Ten, the most for Penn State since 1995–96. DeChellis was named Big Ten Coach of the Year. The Nittany Lions went on to win the 2009 National Invitation Tournament (NIT), the first national tournament title in Penn State Men's Basketball history.
National champion Postseason invitational champion Conference regular season champion Conference regular season and conference tournament champion Division regular season champion Division regular season and conference tournament champion Conference tournament champion